1. Field of the Invention
This invention relates generally to the art of cutting glass and particularly to the art of scoring glass in the presence of a fluid.
2. Description of the Prior Art
The cutting of individual glass articles from a large glass sheet or ribbon is generally accomplished by moving a glass-cutting tool across the surface of the glass with sufficient force to effect a score in the surface of the glass. This may be done with no fluid (dry scoring) or in the presence of a fluid. Cutting fluids may be used for the purpose of lubricating the cutting wheel and axle and the glass, but are now generally used primarily to prevent or retard healing of the score. It is known that healing is retarded by excluding atmospheric moisture from a score. Therefore, cutting fluids are typically in the form of oils or oils mixed with solvents.
U.S. Pat. Nos. 3,894,456 and 3,914,180 to Boller et al. disclose a cutting fluid which comprises methyl chloroform and a non-volatile hydrocarbon oil. The methyl chloroform acts as a cutting tool lubricant, then, being highly volatile, evaporates. The hydrocarbon oil, being non-volatile, forms a residue which binds wing chips along the edge of the score thus preventing spalling. An emulsifying agent may be added to the cutting fluid to aid washability for removal of the non-volatile oil from the glass surface.
Belgian Pat No. 819,914 to Simpkin et al. discloses a cutting fluid comprising a hydrophobic cutting oil and a hydrophobic organic solvent. The oil is thought to reduce lateral cracks produced along the score by water vapor in the atmosphere and consequently to reduce the force required subsequently to snap the glass score while the solvent acts as a thinner and is removed by evaporation.